ADCY5 and type 2 diabetes mellitus: Since the first epigenetic study reported the changes in DNA methylation in pancreatic islets and skeletal muscle in T2DM individuals, numerous studies have revealed the many epigenetic modifications of islet mass and insulin secretion function, including in PDX1, INS, ADCY5, CDKN1A, PDE7B, PPARGC1A, among others.